I don't see him finding that much use due to his unimpressive defenses and in return, making his ability really suck. I can't see him finding many opportunities to switch in, as he is so frail. Also, if the opponent has rocks up, he won't be able to switch in twice before his ability kicking in. Unless you have a way to get him in with a Sub or restoring his health back to 50%+ (or is it 51%+?), I don't see him finding his way onto many teams, as his ability isn't the best, however, it does help to in theory prevent him from being broken, otherwise. However, we won't know.
EDIT: Idk on how his status on being a mixed attacker will stand as... his SpA stat isn't extremely impressive, and with more offensive-based Pokemon that have been introduced, I'm not sure if he will find his own niche being a mixed attacker.